The invention relates to a pressure exchanger for transferring pressure energy from a fluid of one fluid system to a fluid of a second fluid system, comprising a liner and two end covers with an inlet and an outlet passage, respectively, for each fluid, and a cylindrical rotor which is provided in the liner and which is arranged for rotation about its longitudinal axis, and which has a number of through-going channels with an opening at each end arranged symmetrically about the longitudinal axis. The rotor""s channels are arranged for connection with the end covers"" inlet and outlet passages in such a manner that during the rotor""s rotation they alternately conduct fluid at high pressure and fluid at low pressure of the respective systems.
In NO 151341 and 168548 amongst others there is disclosed a pressure exchanger of the above-mentioned type for transferring pressure energy from one fluid flow to another. The pressure exchanger comprises a housing with an inlet and an outlet port for each fluid flow and a rotor which is arranged for rotation about its longitudinal axis in the housing. The rotor has at least one through-going channel, which extends from one end of the rotor to the other end, considered in the axial direction, and alternatively connects the inlet port and the outlet port for one fluid with the outlet port and the inlet port, respectively, for the second fluid and vice versa during the rotor""s rotation.
The rotor is mounted between end covers and in a housing which is subject to full compression stress. At high pressures elastic deformations occur which have a profound effect on internal clearances and fits, a situation which can be partly compensated by means of pressure balancing of the end covers, as described in NO 180599, and by substantial overdimensioning of the rotor""s housing.
In order to achieve a satisfactory degree of reliability in operation when using fluids with low viscosity, e.g., water, it has proved to be necessary to employ ceramics. This is a brittle material with considerably less tensile strength than metals, and at high pressure there is a great risk of fracture if the material should be subjected to impact or shock.
Moreover, pressure exchangers of the above-mentioned type are encumbered with practical drawbacks during maintenance, since pipe couplings have to be opened in order to gain access to internal components. In order to prevent strains in the pipe couplings leading to elastic deformations of critical components, an extra arrangement is required for assembly.
The object of the invention is to provide a pressure exchanger which is not encumbered with the above disadvantages.
The distinctive properties of this pressure exchanger according to the invention are presented in the claims.